Respiratory mask with exhalation valve having alternate biasing means



Oct. 28, 1969 P. ULM N 3,474,783

RESPIRATORY MASK WITH EXHALATION VALVE v I HAVING ALTERNATE BIASINGMEANS Filed Jan. 31. 1967 2 Sheets-Sheet 1 Oct. 28. 1969 P. ULMANN3,474,783

RESPIRATORY MASK WITH EXHALATION VALVE HAVING ALTERNATE BIASING MEANSFiled Jan. 31, 1967 2 Sheets-Sheet 2 EXHALATION VALVE ON A IR INLETUnited States Patent 3,474,783 RESPIRATORY MASK WITH EXHALATION VALVEHAVING ALTERNATE BIASING MEANS Paul Ulmann, Bagnols-sur-Ceze, France,assignor to Commissariat a lEnergie Atomique, Paris, France Filed Jan.31, 1967, Ser. No. 612,974 Claims priority, applicatiozrhFrance, Feb.18, 1966,

Int. Cl. A62b 7 /02; F16k 15/14 US. Cl. 128142.3 Claims ABSTRACT OF THEDISCLOSURE The present invention is directed to an exhalation device forrespiratory masks. It is known that a protective mask or respiratorshould allow the exhaled air to pass through an outlet valve as soon asthe pressure within the mask exceeds the pressure of the surroundingatmosphere by a predetermined difference.

Two types of respiratory masks are in common use. In one type, whichwill be referred-to hereinafter as isolating masks, the face-piece issupplied with a respiratory mixture at a pressure which is distinctlyhigher than that of the surrounding atmosphere (the over-pressure beingusually between 20 and 50 mm. H O) in order to prevent the penetrationof toxic gases or dust particles from the atmosphere through theface-piece at any locations in which leak-tightness is faulty. In thesecond type of respiratory mask, or so-called filtering masks, theface-piece is supplied from the surrounding atmosphere through a filtercartridge and an inlet valve which opens under the action of the reducedpressure or partial vacuum which is developed within the mask as aresult of inhalation by the wearer.

In order to prevent any waste of the respiratory mixture, the exhalationdevice of isolating masks must be calibrated so as to remain closed aslong as the pressure within the mask does not exceed the pressure of theatmosphere by a few millimeters of water in addition to the supplyoverpressure. An exhalation device of this type would not be suitablefor use in filtering masks inasmuch as it would induce considerablerespiratory discom fort in these masks, in which the exhalation devicemust open as soon as the pressure inside the mask becomes higher thanthe ambient pressure. In'short, the devices which are designed forfiltering masks are not suitable for isolating masks inasmuch as theywould permit leakage of the respiratory mixture, and the devices forisolating masks are not comfortable for use under filtering conditions.

However, in a number of dilferent applications and especially in thenuclear industry, it often happens that the same operator is obligedeither for safety reasons or flexibility of use to make use of afiltering mask on some occasions and an isolating mask on otheroccasions. Up to the present time, it was necessary either to change theface-piece or to utilize in all cases an isolating mask exhalationdevice, with the resulting difiiculties in breathing which areexperienced by the wearer.

3,474,783 Patented Oct. 28, 1969 The present invention is intended toprovide an exhalation device for a respiratory mask which can besupplied either from the surrounding atmosphere through a filtercartridge or with a respirable gas which is at overpressure with respectto said atmosphere. The invention is especially characterized in thatthe device comprises a canister fitted with a valve-seat for connectingthe interior of the mask to the atmosphere, a valve which is elasticallyapplied against the valve-seat with slight pressure, elastic meansadapted to cooperate with the valve so as to exert thereon an additionalforce which tends to apply said valve against its seat and which is ofsuflicient intensity to balance said overpressure with respect to thesurrounding atmosphere, and a mechanism for releasing said elasticmeans.

The invention also extends to masks which are fitted on the one handwith a device for supplying a respiratory mixture and a filter cartridgefor supplying the mask from the surrounding atmosphere which can beempolyed alternatively through a suction device and, on the other handwith an exhalation deivce as hereinabove defined. The invention alsoconsists in other arrangements which are preferably employed at the sametime in conjunction with the preceding but which can be employedindepend ently thereof.

A better understanding of the invention will be gained by considerationof the following description of one form of execution which is given byway of non-limitative example, reference being made to the accompanyingdrawings, in which:

FIG. 1 is a view in elevation of an exhalation device as shown in theisolated condition;

" FIG. 2 is a view of the device taken in cross-section on a plane whichpasses through its axis, the parts being shown in the position occupiedfor the purpose of operation with an isolating mask;

FIG. 3, which is similar to FIG. 2, shows the parts in the positionoccupied for the purpose of operation with a filtering mask;

FIG. 4 is a View in cross-section of the device of FIG. 1 with the topremoved, a number of parts being only partly shown for enhancedvisibility of other parts located beneath;

FIG. 5 is a detail view of the check valve and is intended to show thedeformation to which said valve is subjected when in position and atrest within the device.

FIG. 6 is a view of a prior art mask showing the location of theexhalation device or valve.

The device which is shown in FIGS. 1 to 4 comprises a canister A inwhich is mounted a normally-closed valve B. The casing A comprises acylindrical body 6 which is secured in leak-tight manner to a skirt 10of the facepiece C by means of a fastening collar 8 (as shown in FIGS. 2and 3) and a cover 12. Said cover has a cylindrical skirt and a convexbase 14 pierced by a series of uniformly spaced apertures 16. The skirtis provided with a circular internal boss 18 for engaging the cover 12within a channel 20 of the body 6.

The top face of the canister body 6 has a circular rib of roundedtransverse section which constitutes a valveseat 22, said seat beingadapted to surround a communication passageway between the interior ofthe face-piece C and the cover 12. The exhalation or outlet valve isformed by the combination of said seat 22 and a gate 24 which iscomposed of a stem 26 and a flat diaphragm 32. The stem 26 has anarrowed portion 28 which is stationarily fixed in a recess formed in ahub of the body which is joined to the peripheral portion by means ofthree arms 30. The arms 30 are adapted to retai a screen 34 which isplaced between the diaphragm 32 and the interior of the face-piece C (asshown in FIGS. 2, 3 and 4).

The valve-seat 22 and recess in which the stem 26 is imprisoned have arelative axial location such that, when the gate 24 is in position, thediaphragm 32 is slightly deformed, as is apparent from FIG. which showsthe amplitude a of the deformation. The natural elasticity of thematerial constituting the gate thus tends to apply said gate against theseat 22 with a force which can be of a very low order.

There are also fitted in the cover 12 elastic means which tend toincrease the force with which the diaphragm 32 of the gate 24 is appliedagainst its seat 22 (as shown in FIGS. 2 and 3). These means comprise acup 36 provided in the central portion with three apertures for thepassage of air to the surrounding atmosphere. The axial displacement ofsaid cup 36 is guided by three rectilineal bosses 38 formed on the skirtof the cover 12 and disposed at an angle of 120 relatively to eachother. A spiral spring 40 which is compressed between the bottom 14 ofthe cover 12 and the cup 36 serves to apply this latter against theperiphery of the diaphragm 32.

The cup 32 is rigidly fixed by any suitable means such as the screws 44which are shown in FIGS. 1 to 4 to a control ring 46 which is adapted toslide over the outer cylindrical wall of the skirt of the cover 12.

The L-shaped guide slots which are formed in the skirt of the cover 12permit the sliding motion of the screws 44; when the ring 46 is orientedin such a manner that the screws 44 are placed in that portion of theslots 48 which is parallel to the axis (as shown in FIGS. 1 and 2), thespring 40 thrusts back the cup 36 towards the gate 24 and adds itstension to the elasticity of the gate so as to shut off the outletvalve. On the other hand, when the ring 46 is raised and oriented so asto lock the screws 44 in that portion of the guide slots 48 which isperpendicular to the axis, the spring 40 cannot produce action on thegate 24 (as shown in FIG. 3).

The operation of the device is apparent from the foregoing descriptionand will therefore be discussed only in brief outline.

When the ring 46 is free (as shown in FIG. 2), the

spring 40 applies said ring against the edge of the dia phragm 32. Theforce exerted by the spring 40 which is added to the elasticity of thediaphragm is sufficient to maintain the outlet valve in the closedposition as long as only the normal supply overpressure of the mask isexerted on the diaphragm. It is only when the overpressure produced bythe breath exhaled by the wearer is higher than the normal overpressurethat the outlet valve opens to release the exhaled air. When the wearerof the mask has to operate this latter as a filter, using filtercartridge 51 (FIG. 6) for example in order to switch from one point ofsupply of respiratory mixture 50 (FIG. 6) to another, it is merelynecessary in that case to remove the ring 46 and to rotate this latterto a slight extent in order to lock it in position (as shovm in FIG. 3).The cup 36 which is maintained in the top position retains the spring40. The outlet valve is then free and the diaphragm 32 rises in the caseof very low values of overpressure within the mask with respect to theambient pressure, thereby preventing any difliculty in breathing.Moreover,.the diaphragm 32 is capable of reversal (position shown inchain-dotted lines in FIG. 3) in order to permit high flow rates.

What I claim is:

1. An exhalation device for respiratory masks, comprising a canister, avalve-seat in said canister forming a passageway connecting the interiorof the .mask to the atmosphere, a valve elastically applied against saidseat with slight pressure, resilient means cooperating with said valveto exert thereon an additional force applying said valve against itsseat, mechanism for releasing said resilient means and freeing saidvalve therefrom, said resilient means being a spring interposed betweensaid canister and a cup bearing on said valve, said bearing cup beingrigidly fixed to a control ring slidably mounted on the outer wall ofthe canister said releasing mechanism locking said ring on said canisterin a position in which said cup does not bear on said valve.

2. A device in accordance with claim 1, said cup and said ring beingcoupled by screws passing through L- shaped slots in said canister, saidslots having a circular portion cooperating with said screws providingsaid release mechanism.

3. A respiratory mask comprising an exhalation device in accordance withclaim 2, wherein said mask can be supplied either from the surroundingatmosphere through a filter cartridge or with a respirable gas which isat overpressure with respect to the atmosphere, and wherein saidadditional force is of sufficient intensity to balance said overpressurewith respect to the surrounding atmosphere.

4. A respiratory mask in accordance with claim 3, wherein said maskcomprises a device for supplying a respiratory mixture and a filtercartridge for supplying air from the surrounding atmosphere which can beemployed alternately through a suction device whereby the interior ofthe mask can be connected either to the respiratory-mixture supply or tothe filtered-air supply.

'5. An exhalation device for respiratory masks comprising a canister, agas passageway in said canister con necting the interior of the mask tothe atmosphere, a valve seat in said canister, a closure membercooporating with said valve seat to open and close said gas passagewayin response to changes of gas pressure within the mask, meansresiliently biasing said member to a position'in which said passagewayis closed, supplementary biasing means movable between a first positionin which said means resiliently act on said closure member toadditionally bias said member to its closed position and a secondposition in which said means disengage said closure member, and manuallyactuable control means for moving said supplementary biasing meansbetween said first and second positions and locking said supplementarybiasing means in said second position.

References Cited UNITED STATES PATENTS 3,199,524 8/1965 Mitchell 137-529XR FOREIGN PATENTS 74,330 6/ 1952 Denmark. 705,216 3/1954 Great Britain.

L. W. TRAPP, Primary Examiner U.S. Cl. X.R. l37529; 251176

